JP5556832B2 - Valve lift adjustment device - Google Patents

Description

  The present invention relates to a valve lift adjusting device.

  2. Description of the Related Art A valve lift adjustment device is known that includes two types of plate cams that can convert rotational movement of a cam shaft of an internal combustion engine into reciprocating linear motion of an engine valve, and adjusts the valve lift of the engine valve by switching each plate cam. Yes. In the valve lift adjusting device disclosed in Patent Document 1, the two types of plate cams are fitted so as to be able to transmit rotation to the cam shaft and be relatively movable in the axial direction. The plate cams are adjacent to each other in the axial direction and are integrally formed with each other. Each plate cam is switched by a slider.

  The slider is a cylindrical member that moves in the axial direction integrally with the plate cam. The slider has a meandering groove on its outer wall, and its axial position is regulated by a regulating pin inserted into this groove. In Patent Document 1, the front half of the groove is for moving the slider so as to switch to one plate cam. Further, the latter half of the groove is for moving the slider so as to switch to the other plate cam. The valve lift adjusting device moves the slider to two axial positions with one regulating pin.

US Patent Application Publication No. 2011/0247577

  In the valve lift adjusting device disclosed in Patent Document 1, it is necessary to insert the regulating pin into the groove while the slider rotates about ¼ turn. Therefore, the drive part of a control pin needs to operate a control pin quickly. The operating speed of the drive unit needs to be higher as the rotational speed of the internal combustion engine is higher. When the insertion of the restriction pin into the groove is delayed, there is a problem that the engagement between the restriction pin and the groove becomes shallow or disengaged.

  In order to solve the above problem, it is conceivable that the operation start timing of the regulation pin is advanced. However, if the operation start timing of the restriction pin is advanced, for example, when the restriction pin is inserted into the first half of the groove, the restriction pin may be engaged with the second half of the groove, resulting in an excessive load on the restriction pin. There is.

  The present invention has been made in view of the above-described points, and an object of the present invention is to be able to move the slider to two axial positions with one restricting member and to reliably insert the restricting pin into the groove. It is providing the valve lift adjustment apparatus which can be performed.

  The present invention is a valve lift adjusting device for adjusting a valve lift of an engine valve of an internal combustion engine, and includes a first plate cam and a second plate cam fitted to a cam shaft, rotation transmission to the cam shaft and an axial direction. A cylindrical slider connected so as to be relatively movable, a restricting member that can be inserted into and removed from an engaging groove on a radially outer wall of the slider, and a drive unit that inserts the restricting member into the engaging groove to operate.

  The slider includes a first plate cam and a second plate in an axial direction between a first operating position where the engine valve is interlocked with the first plate cam and a second operating position where the engine valve is interlocked with the second plate cam. It can move together with the cam.

The restricting member is inserted into the engaging groove when the cam shaft rotates and engages the first slope of the engaging groove to move the slider to the second operating position, and is inserted into the engaging groove when the cam shaft rotates. When engaged with the second inclined surface of the engagement groove, the slider is moved to the first operating position.
Therefore, according to the present invention, the slider can be moved to two axial positions by one regulating member.

The present invention also includes a speed reduction means for reducing the rotation of the camshaft and transmitting it to the slider.
Therefore, according to the present invention, since the rotation of the slider is slower than the rotation of the camshaft, the restricting member can be surely inserted into the engagement groove even if the operation speed of the drive unit is relatively slow. Furthermore, it is possible to reduce the load acting on the regulating member from the inner wall of the engaging groove of the slider.

It is a figure which shows the valve system using the valve lift adjustment apparatus by 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows the valve system seen from the arrow V direction of FIG. It is a perspective view which shows the 1st protrusion side among the sliders of FIG. It is a perspective view which shows the 2nd protrusion side among the sliders of FIG. It is a figure which shows the state in which the control pin which protruded in the slider side from the state of FIG. 2 was inserted in the engaging groove. It is a figure which shows the state which the slider moved to the 2nd operation position from the state of FIG. FIG. 10 is a diagram illustrating a state in which a restriction pin protruding from the state of FIG. 9 to the slider side is inserted into the engagement groove. It is a figure which shows the valve system using the valve lift adjustment apparatus by 2nd Embodiment of this invention. It is a figure which shows the valve system using the valve lift adjustment apparatus by 3rd Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
The valve lift adjusting device according to the first embodiment of the present invention is a variable valve mechanism of a cam switching type and is used in the valve system shown in FIG. The valve system 20 is a system that opens and closes an intake valve 44 of an internal combustion engine.

  As shown in FIGS. 1 to 5, the valve system 20 includes a camshaft 21, a low rotation cam 25, a high rotation cam 30, a roller rocker 40, a lash adjuster 43, an intake valve 44, a slider 50, an actuator 70, and a deceleration. Means 80 are provided.

  The low-rotation cam 25, the high-rotation cam 30, the slider 50, the actuator 70, and the speed reduction means 80 constitute the valve lift adjusting device 10. The low rotation cam 25 corresponds to a “first plate cam” described in the claims, and the high rotation cam 30 corresponds to a “second plate cam” described in the claims.

  The cam shaft 21 is rotatably supported by a cylinder head 12 at a location not shown. As shown in FIG. 2 to FIG. 4, spline external teeth extending in the axial direction are formed on the radially outer wall of the cam shaft 21. An output shaft of an internal combustion engine (not shown) is connected to the camshaft 21 via a timing chain or the like. The cam shaft 21 rotates integrally with the output shaft.

The low rotation cam 25, the high rotation cam 30, and the first external gear 81 of the speed reduction means 80 are made of the same member and are formed integrally with each other.
The low-rotation cam 25 is a disc cam that is fitted to the cam shaft 21. A cam lobe 27 protruding from the base circle 26 in the radially outward direction is formed on the radially outer wall of the low rotation cam 25.

  Spline inner teeth extending in the axial direction are formed on the inner diameter wall of the low-rotation cam 25. The spline inner teeth mesh with the spline outer teeth of the camshaft 21. The low-rotation cam 25 is connected to the cam shaft 21 so as to be capable of transmitting rotation and relatively moving in the axial direction.

  The low-rotation cam 25 and the roller rocker 40 constitute a low-rotation cam mechanism that converts the rotational motion of the cam shaft 21 into the reciprocating linear motion of the intake valve 44. In the low rotation cam mechanism, the low rotation cam 25 functions as an original node, and the roller rocker 40 functions as a follower.

  The high rotation cam 30 is a disc cam fitted to the cam shaft 21 and is adjacent to the low rotation cam 25 in the axial direction. A cam lobe 32 protruding from the base circle 31 by a predetermined amount in the radially outward direction is formed on the radially outer wall of the high rotation cam 30. The base circle 26 and the base circle 31 are formed in the same plane with no step.

  The cam profile of the high rotation cam 30 is different from the cam profile of the low rotation cam 25. For example, the maximum cam lift of the high rotation cam 30 is larger than the maximum cam lift of the low rotation cam 25. Further, the cam operating angle of the high rotation cam 30 is larger than the cam operating angle of the low rotation cam 25.

  Spline inner teeth extending in the axial direction are formed on the inner wall of the high-rotation cam 30. The spline inner teeth mesh with the spline outer teeth of the camshaft 21. The high-rotation cam 30 is connected to the cam shaft 21 so as to be capable of transmitting rotation and relatively moving in the axial direction.

  The high-rotation cam 30 and the roller rocker 40 constitute a high-rotation cam mechanism that converts the rotational motion of the cam shaft 21 into the reciprocating linear motion of the intake valve 44. In the high rotation cam mechanism, the high rotation cam 30 functions as an original node, and the roller rocker 40 functions as a follower.

The roller rocker 40 includes a swing arm 41 and a roller 42.
The swing arm 41 has one end in contact with the lash adjuster 43 and the other end in contact with the tip of the stem 45 of the intake valve 44. The swing arm 41 can swing so that the other end approaches and separates from the camshaft 21 with one end serving as a fulcrum.

  The roller 42 is provided between one end and the other end of the swing arm 41. As shown in FIG. 1, the roller 42 contacts the radially outer wall of the low-rotation cam 25 when each cam and the slider 50 are positioned on one side in the axial direction. The axial position of each cam and slider 50 at this time is defined as a “first operating position”.

  Further, as shown in FIG. 9 described later, the roller 42 comes into contact with the outer radial wall of the high-rotation cam 30 when each cam and the slider 50 are positioned on the other side in the axial direction. The axial position of each cam and slider 50 at this time is defined as a “second operating position”.

  1 to 5, the intake valve 44 is a poppet valve and can open and close the intake port of the cylinder of the internal combustion engine. The intake valve 44 is urged in the valve closing direction by a spring (not shown), and when the intake valve 44 is pushed by the cam lobe 27 of the low-rotation cam 25 or the cam lobe 32 of the high-rotation cam 30 through the swing arm 41, the intake port Is released.

  The slider 50 is formed in a cylindrical shape and is adjacent to the low rotation cam 25 in the axial direction on the opposite side of the high rotation cam 30. Further, the slider 50 can rotate around an axis that is eccentric with respect to the cam shaft 21, and can move relative to the cam shaft 21 in the axial direction. The cam shaft 21 passes through the slider 50. A reduction means 80 is provided in the radial direction of the slider 50. The slider 50 is connected to the camshaft 21 via the speed reduction means 80 so as to be able to transmit rotation. The speed reduction means 80 will be described in detail later.

  The slider 50 can move integrally with each cam in the axial direction between the first operating position and the second operating position. The first operation position is a position where the intake valve 44 is interlocked with the low-rotation cam 25. The second operating position is a position at which the intake valve 44 is interlocked with the high rotation cam 30. When the slider 50 moves in the axial direction, each cam moves together with the slider 50.

  The outer diameter wall of the slider 50 has an engagement groove 51 extending in the circumferential direction. In the present embodiment, the axial width of the engagement groove 51 is the same over the entire circumference. Further, the engaging groove 51 extends in a direction orthogonal to the axial direction of the slider 50.

  Assuming that one of the inner walls of the engagement groove 51 in the axial direction is the first wall 52 and the other wall is the second wall 53, the first wall 52 is closer to the rear side in the rotational direction of the slider 50. A first protrusion 54 protruding toward 53 is formed. The first inclined surface 55 on the front side in the rotational direction of the first protrusion 54 is configured such that when each cam and the slider 50 are positioned at the first operating position and the slider 50 is rotating, the slider is engaged with the restriction pin 71. 50 is moved to the second operating position.

  The second wall 53 forms a second protrusion 58 that protrudes toward the first wall 52 toward the rear side in the rotational direction at a position different from the first protrusion 54 in the circumferential direction. The second inclined surface 59 on the front side in the rotational direction of the second protrusion 58 is configured such that when each cam and the slider 50 are positioned at the second operation position and the slider 50 is rotating, the slider is engaged with the restriction pin 71. 50 is moved to the first operating position.

  The bottom wall of the engagement groove 51 has a first upward surface 64 and a second upward surface 66. The first rising surface 64 is a slope whose depth from the outer surface 68 of the slider 50 decreases toward the rear end 57 in the rotation direction of the first protrusion 54. The second rising surface 66 is a slope whose depth from the outer surface 68 of the slider 50 decreases toward the rear end 61 in the rotation direction of the second protrusion 58.

The actuator 70 is a linear operation type electromagnetic actuator, is fixed to the cylinder head 12, and includes a regulation pin 71 and a drive unit 73.
The restriction pin 71 corresponds to a “restriction member” recited in the claims, and is arranged such that the axial direction of the restriction pin 71 coincides with the radial direction of the slider 50. The restriction pin 71 is movable in the direction approaching and separating from the slider 50, that is, in the axial direction.

  When the regulation pin 71 approaches the slider 50, the tip end portion is inserted into the engagement groove 51, and when the restriction pin 71 is separated from the slider 50, the tip end portion comes out of the engagement groove 51. That is, the regulation pin 71 can be inserted into and removed from the engagement groove 51. When the restriction pin 71 is inserted into the engagement groove 51, the restriction pin 71 engages with the inner wall of the engagement groove 51 to restrict the position of the slider 50 in the axial direction.

  The drive unit 73 includes a sleeve 74 that supports the restriction pin 71 so as to be reciprocally movable, a fixed core 75 that is fixed to the inner wall of the sleeve 74, and a movable core 77 that is fixed to the end of the restriction pin 71 within the sleeve 74. And a coil 79 made of a winding wound around a fixed core 75 and generating a magnetic field when energized.

  The movable core 77 includes a permanent magnet that repels the fixed core 75 magnetized by the magnetic field of the coil 79. The drive unit 73 inserts the regulation pin 71 into the engagement groove 51 by energizing the coil 79 and separating the movable core 77 from the fixed core 75. Further, the drive unit 73 allows the restriction pin 71 to come out of the engagement groove 51 by stopping energization of the coil 79 and releasing the magnetization of the fixed core 75.

  When the drive unit 73 moves the slider 50 from the first operating position of FIG. 1 to the second operating position of FIG. 9, when the circumferential relative position of the restricting pin 71 with respect to the slider 50 coincides with the first protrusion 54, the restricting pin The operation for inserting 71 into the engaging groove 51 is started. Further, when moving the slider 50 from the first operation position to the second operation position, the drive unit 73 stops energization when the circumferential relative position of the restriction pin 71 with respect to the slider 50 coincides with the first upward surface 64.

  When the drive unit 73 moves the slider 50 from the second operating position of FIG. 9 to the first operating position of FIG. 1, when the circumferential relative position of the restricting pin 71 with respect to the slider 50 coincides with the second protrusion 58, the restricting pin The operation for inserting 71 into the engaging groove 51 is started. Further, when moving the slider 50 from the second operating position to the first operating position, the driving unit 73 stops energization when the circumferential relative position of the restriction pin 71 with respect to the slider 50 coincides with the second upward surface 66.

The speed reducer 80 decelerates the rotation of the camshaft 21 and transmits it to the slider 50, and includes a first external gear 81 and an internal gear 83.
The first external gear 81 is adjacent to the low rotation cam 25 on the opposite side of the high rotation cam 30 in the axial direction, and rotates integrally with the low rotation cam 25 and the high rotation cam 30. The first external gear 81 has a cylindrical shape and is fitted to the camshaft 21 so as to be capable of transmitting rotation and relatively moving in the axial direction.

  The first external gear 81 has a flange 82 that protrudes radially outward from the end opposite to the low-rotation cam 25. The collar portion 82 holds the slider 50 together with the low-rotation cam 25. The axial force of the slider 50 moving to the low rotation cam 25 side is transmitted to each cam via the low rotation cam 25. Further, the axial force of the slider 50 that moves toward the flange portion 82 is transmitted to each cam via the first external gear 81.

  The internal gear 83 and the slider 50 are made of the same member and are integrally formed with each other. The internal gear 83 rotates integrally with the slider 50. The internal gear 83 is positioned radially inward with respect to the slider 50 and is disposed coaxially with the slider 50 and meshes with the first external gear 81.

  The speed reducer 80 decelerates the rotation of the cam shaft 21 and transmits it to the slider 50. If the slider 50 is on the driven side, the reduction ratio of the reduction means 80 is 2. That is, the number of teeth of the internal gear 83 is twice the number of teeth of the first external gear 81. The rotational speed of the slider 50 is ½ times the rotational speed of the cam shaft 21.

Next, the operation of the valve system 20 will be described with reference to FIGS. 1 and 8 to 10.
As shown in FIG. 1, when the cam shaft 21 rotates when the slider 50 is located at the first operating position, the rotational motion of the low-rotation cam 25 is transmitted to the swing arm 41 via the roller 42, and the intake valve 44 Converted to reciprocating linear motion.

  In the state of FIG. 1, for example, when the engine speed reaches a high rotation range, when the circumferential relative position of the restriction pin 71 with respect to the slider 50 coincides with the first protrusion 54, the drive unit 73 pushes the restriction pin 71 into the engagement groove 51. The operation to plug in is started. The restriction pin 71 is inserted into the engagement groove 51 after the relative position in the circumferential direction with respect to the slider 50 coincides with the first protrusion 54 until the first protrusion 54 is reached next. That is, the restriction pin 71 is inserted into the engagement groove 51 between the time when the circumferential relative position coincides with the first protrusion 54 and the time when the cam shaft 21 rotates twice.

  As shown in FIG. 8, when the slider 50 rotates together with the cam shaft 21 with the restriction pin 71 inserted into the engagement groove 51, the first inclined surface 55 of the first protrusion 54 of the slider 50 engages with the restriction pin 71. The position of the slider 50 in the axial direction is restricted, and the slider 50 slides to the second operating position side as indicated by an arrow A1 in FIG. When the slider 50 slides toward the second operating position, the drive unit 73 stops energization. At this time, the restricting pin 71 is pushed in the radially outward direction by the first rising surface 64 of the engaging groove 51 and comes out of the engaging groove 51 and returns in the radially outward direction.

  As shown in FIG. 9, when the cam shaft 21 rotates when the slider 50 is located at the second operating position, the rotational motion of the high-rotation cam 30 is transmitted to the swing arm 41 via the roller 42, and the intake valve 44 Converted to reciprocating linear motion. When the rotational motion of the high-rotation cam 30 is converted into the reciprocating linear motion of the intake valve 44, the valve lift is larger than when the rotational motion of the low-rotation cam 25 is converted into the reciprocating linear motion of the intake valve 44. Become.

  In the state of FIG. 9, for example, when the engine speed reaches a low rotation range, when the circumferential relative position of the restriction pin 71 with respect to the slider 50 coincides with the second protrusion 58, the drive unit 73 pushes the restriction pin 71 into the engagement groove 51. The operation to plug in is started. The restriction pin 71 is inserted into the engagement groove 51 after the relative position in the circumferential direction with respect to the slider 50 coincides with the second protrusion 58 and until the second protrusion 58 is reached next. That is, the restriction pin 71 is inserted into the engagement groove 51 between the time when the circumferential relative position coincides with the second protrusion 58 and the time when the cam shaft 21 rotates twice.

  As shown in FIG. 10, when the slider 50 rotates together with the cam shaft 21 with the restriction pin 71 inserted into the engagement groove 51, the second inclined surface 59 of the second protrusion 58 of the slider 50 engages with the restriction pin 71. The position of the slider 50 in the axial direction is restricted, and the slider 50 slides to the first operating position side as indicated by an arrow A2 in FIG. When the slider 50 slides toward the first operating position, the drive unit 73 stops energization. At this time, the restricting pin 71 is pushed in the radially outward direction by the second rising surface 66 of the engaging groove 51 and comes out of the engaging groove 51 and returns in the radially outward direction.

  As described above, in the valve lift adjusting device 10 according to the present embodiment, the first wall 52 of the engagement groove 51 of the slider 50 protrudes toward the second wall 53 toward the rear side in the rotational direction, and the slider 50 A first protrusion 54 is formed to move the slider 50 from the first operating position to the second operating position when engaged with the restriction pin 71 during rotation. The restriction pin 71 is inserted into the engagement groove 51 when the cam shaft 21 rotates and engages with the first inclined surface 55 of the first protrusion 54 to move the slider 50 to the second operating position.

The second wall 53 protrudes toward the first wall 52 toward the rear side in the rotational direction at a position different from the first protrusion 54 in the circumferential direction, and when the slider 50 is rotated, the second wall 53 is engaged with the restriction pin 71. A second protrusion 58 is formed to move 50 from the second operating position to the first operating position. When the restricting pin 71 is inserted into the engaging groove 51 when the cam shaft 21 rotates and engages with the second inclined surface 59 of the second protrusion 58, the restricting pin 71 moves the slider 50 to the first operating position.
Therefore, according to the valve lift adjusting device 10, the slider 50 can be moved to the first operating position and the second operating position with one restriction pin 71.

Further, the valve lift adjusting device 10 includes a speed reduction unit 80 that reduces the rotation of the camshaft 21 and transmits it to the slider 50.
Therefore, according to the valve lift adjusting device 10, since the rotation of the slider 50 is slower than the rotation of the cam shaft 21, the restriction pin 71 is reliably inserted into the engagement groove 51 even when the operation speed of the drive unit 73 is relatively slow. Can be plugged in. Furthermore, the load acting on the regulation pin 71 from the inner wall of the engagement groove 51 of the slider 50 can be reduced.

Further, in this embodiment, when the slider 50 is on the driven side in the speed reduction means 80, the speed reduction ratio of the speed reduction means 80 is 2.
Therefore, the drive unit 73 inserts the restriction pin 71 into the engagement groove 51 after the circumferential relative position of the restriction pin 71 with respect to the slider 50 coincides with the first protrusion 54 until the camshaft 21 rotates twice. That's fine. Therefore, the restriction pin 71 can be reliably inserted into the engagement groove 51 even if the operating speed of the drive unit 73 is relatively slow.

In the present embodiment, the speed reduction means 80 is engaged with the first external gear 81 that rotates integrally with the low-rotation cam 25 and the high-rotation cam 30, meshes with the first external gear 81, and rotates integrally with the slider 50. And an internal gear 83.
Therefore, the structure of the speed reduction means 80 is simple.

(Second Embodiment)
A valve lift adjusting device according to a second embodiment of the present invention will be described with reference to FIG.
The valve lift adjusting device 90 includes a slider 91 and a speed reducing unit 92. The slider 91 can rotate around an axis parallel to the cam shaft 21 and can move relative to the cam shaft 21 in the axial direction. The slider 91 can move integrally with each cam in the axial direction between the first operating position and the second operating position.

The slider 91 is connected to the camshaft 21 via the speed reduction means 92 so as to be able to transmit rotation. The speed reducing means 80 includes a second external gear 93 and a third external gear 95.
The second external gear 93 is adjacent to the low rotation cam 25 on the opposite side of the high rotation cam 30 in the axial direction. The second external gear 93, the low-rotation cam 25, and the high-rotation cam 30 are made of the same member and are integrally formed with each other. The second external gear 93 can transmit rotation to the cam shaft 21 and can move relative to the axial direction.

  The third external gear 95 is adjacent to the slider 91 in the axial direction, is disposed coaxially with the slider 91, and meshes with the second external gear 93. The third external gear 95 and the slider 91 are made of the same member and are integrally formed with each other.

  The second external gear 93 has a flange 94 that protrudes radially outward from the end opposite to the low-rotation cam 25. The flange 94 holds the third external gear 95 together with the low rotation cam 25. The axial force of the third external gear 95 moving to the low rotation cam 25 side is directly transmitted to each cam, and the axial force of the third external gear 95 moving to the flange portion 82 side is It is transmitted to each cam via the part 94. When the slider 91 moves in the axial direction, each cam moves together with the slider 91.

The speed reducer 92 decelerates the rotation of the cam shaft 21 and transmits it to the slider 91. If the slider 91 is on the driven side, the reduction ratio of the reduction means 92 is 2. That is, the number of teeth of the third external gear 95 is twice the number of teeth of the second external gear 93. The rotational speed of the slider 91 is ½ times the rotational speed of the cam shaft 21.
According to 2nd Embodiment, there exists an effect similar to 1st Embodiment.

(Third embodiment)
A valve lift adjusting apparatus according to a third embodiment of the present invention will be described with reference to FIG.
The valve lift adjusting device 100 includes a slider 101 and a speed reduction means 102. The slider 101 is adjacent to the low-rotation cam 25 on the opposite side of the high-rotation cam 30 and is disposed coaxially with the cam shaft 21 so as to be rotatable relative to the cam shaft 21 and movable in the axial direction. is there. The slider 101 can move integrally with each cam in the axial direction between the first operating position and the second operating position.

  The slider 101 is connected to the camshaft 21 via the speed reduction means 102 so as to be able to transmit rotation. The speed reduction means 102 includes a fourth external gear 103, a fifth external gear 105, a sixth external gear 106, and a seventh external gear 107.

  The fourth external gear 103 is positioned on the opposite side of the low rotation cam 25 with respect to the slider 101 in the axial direction. The fourth external gear 103 has a connection portion 104 that extends toward the low-rotation cam 25 in the radial inner direction of the slider 101. The fourth external gear 103, the low rotation cam 25, and the high rotation cam 30 are made of the same member and are integrally formed with each other. The fourth external gear 103 can transmit rotation to the cam shaft 21 and can move relative to the axial direction.

The fifth external gear 105 is rotatable around an axis parallel to the cam shaft 21 and meshes with the fourth external gear 103.
The sixth external gear 106 is adjacent to the slider 101 side with respect to the fifth external gear 105 and is disposed coaxially with the fifth external gear 105. The fifth external gear 105 and the sixth external gear 106 are made of the same member and are integrally formed with each other.

  The seventh external gear 107 is located between the slider 101 and the fourth external gear 103, is arranged coaxially with the cam shaft 21, and meshes with the sixth external gear 106. The seventh external gear 107 and the slider 101 are made of the same member and are integrally formed with each other.

  The slider 101 is held between the low rotation cam 25 and the fourth external gear 103 in the axial direction. The axial force of the slider 101 moving to the low rotation cam 25 side is directly transmitted to each cam, and the axial force of the slider 101 moving to the fourth external gear 103 side is applied to each cam via the fourth external gear 103. Communicated. When the slider 101 moves in the axial direction, each cam moves together with the slider 101.

The deceleration means 102 decelerates the rotation of the cam shaft 21 and transmits it to the slider 101. If the slider 101 is on the driven side, the reduction ratio of the reduction means 102 is 2. The rotational speed of the slider 101 is ½ times the rotational speed of the cam shaft 21.
According to 3rd Embodiment, there exists an effect similar to 1st Embodiment.

(Other embodiments)
In other embodiments of the present invention, the speed reduction means may be realized with other mechanical configurations. For example, you may comprise with other gear reducers, such as a planetary gear reducer, and you may comprise with other types of reducers, such as a belt type reduction gear comprised from the pulley and the belt.

In another embodiment of the present invention, the reduction ratio of the reduction means may be an integer of 3 or more. Further, it may be a value such that the integer multiple is 1.5, such as 1.5.
In other embodiments of the present invention, the axial width of the engagement groove may be different in the circumferential direction.
In another embodiment of the present invention, the engagement groove may be formed at a predetermined angle with respect to the axial direction.

Other embodiments of the invention may be used in a valve system for an exhaust valve.
Other embodiments of the present invention are not limited to valve systems that include roller rockers with swing arms, and may be used with other types of valve systems.

  In another embodiment of the present invention, two or more valve lift adjusting devices may be provided for one engine valve. For example, three cams may be provided, and the slider may be moved to three axial positions by two restriction pins.

In another embodiment of the present invention, each cam and slider may be coupled to the camshaft by a fitting method other than spline fitting.
In another embodiment of the present invention, the spline internal teeth that engage with the camshaft need only be formed on at least a part of each cam and slider.

  In other embodiments of the present invention, the cam profile of the high rotation cam may make any difference to the cam profile of the low rotation cam. For example, the maximum cam lift may be the same and the cam operating angle may be different. Further, the cam operating angle is the same, and the maximum cam lift may be varied. Further, the maximum cam lift and the cam operating angle are the same, and the valve opening / closing timing may be varied.

  The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

10, 90, 100 ... Valve lift adjusting device 21 ... Cam shaft 25 ... Low rotation cam (first plate cam)
30 ... High rotation cam (second plate cam)
44 ... Intake valve (engine valve)
50, 91, 101 ... Slider 51 ... Engaging groove 55 ... First slope 59 ... Second slope 71 ... Restriction pin (regulation member)
73: Drive unit 80, 92, 102 ... Deceleration means

Claims (5)

A valve lift adjusting device (10, 90, 100) for adjusting a valve lift of an engine valve (44) of an internal combustion engine,
The camshaft (21) that rotates integrally with the output shaft of the internal combustion engine is fitted so as to be capable of transmitting rotation and relatively movable in the axial direction, and the rotational motion of the camshaft can be converted into the reciprocating linear motion of the engine valve. A first plate cam (25);
Fitted to the camshaft so that it can transmit rotation and move in the axial direction, and has a cam profile different from that of the first plate cam, and can convert the rotational movement of the camshaft to the reciprocating linear movement of the engine valve. Second plate cam (30),
The engine valve is formed in a cylindrical shape, is connected to the first plate cam and the second plate cam so as to be able to transmit rotation, and has an engagement groove (51) extending in a circumferential direction on a radially outer wall. Is moved together with the first plate cam and the second plate cam between a first operation position for interlocking with the first plate cam and a second operation position for interlocking the engine valve with the second plate cam. Possible sliders (50, 91, 101);
When the camshaft rotates, the slider is moved to the second operating position when it is inserted into the engagement groove and engages with the first inclined surface (55) of the engagement groove. A regulating member (71) for moving the slider to the first operating position when the camshaft rotates and is inserted into the engaging groove and engages with the second inclined surface (59) of the engaging groove;
A drive unit (73) for inserting and operating the regulating member into the engaging groove;
Deceleration means (80, 92, 102) for decelerating the rotation of the camshaft and transmitting it to the slider;
A valve lift adjusting device comprising:   2. The valve lift adjustment device according to claim 1, wherein a reduction ratio of the reduction means is 2 or 3 when the slider is driven. The slider (50) is disposed radially outward with respect to the cam shaft and is eccentric with respect to the cam shaft,
The speed reduction means (80) includes a first external gear (81) that rotates integrally with the first plate cam and the second plate cam, and an internal gear that meshes with the first external gear and rotates integrally with the slider. The valve lift adjusting device (10) according to claim 1 or 2, characterized by comprising (83). The slider (91) is provided to be rotatable around an axis parallel to the cam shaft,
The speed reduction means (92) includes a second external gear (93) that rotates integrally with the first plate cam and the second plate cam, and a third external gear that meshes with the second external gear and rotates integrally with the slider. The valve lift adjusting device (90) according to claim 1 or 2, characterized in that it comprises an external gear (95). The slider (101) is disposed coaxially with the cam shaft,
The speed reduction means (102) is eccentric with respect to the fourth external gear and meshes with the fourth external gear, and a fourth external gear (103) that rotates integrally with the first plate cam and the second plate cam. A fifth external gear (105), a sixth external gear (106) disposed coaxially with the fifth gear and rotating integrally with the fifth external gear, and coaxially disposed with the fourth gear; The valve lift adjusting device (100) according to claim 1 or 2, wherein the valve lift adjusting device (100) is constituted by a seventh external gear (107) meshing with the sixth external gear and rotating integrally with the slider.

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